Communication systems allow users to communicate with each other over a network. The network may be, for example, the internet or the Public Switched Telephone Network (PSTN). Audio signals can be transmitted between nodes of the network, to thereby allow users to transmit and receive audio data (such as speech data) to each other in a communication session over the communication system. A microphone can be used at a user device to receive audio signals (e.g. speech) from a user for transmission to a remote node in a communication session. As well as the audio signals from the user, the microphone may also receive other audio signals, such as background noise, which may disturb the audio signals received from the user.
A user device comprising audio input means such as a microphone for receiving audio signals from a user may also have audio output means such as speakers for outputting audio signals to the user. When in a communication session, the speakers are intended to output audio signals from an application handling calls over the communication system. However, the speakers may also be used to output audio signals from other applications which are executed at the user device. For example, the user device may be a mobile phone which has an application for playing music through the speakers. When the user device is engaging in a call, the microphone of the audio device is intended to receive speech or other audio signals provided by the user intended for transmission to a remote node in a communication session. However, the microphone may pick up unwanted audio signals which are output from the speakers of the user device. The unwanted audio signals output from the user device may contribute to disturbance to the primary audio signals received at the microphone from the user for transmission in the call. There are two approaches for addressing this situation.
In a first approach, media output may be suppressed when a call is received such that the audio output is available for the call only. For example, some mobile phones that have mp3 players will pause the music when the mobile phone is engaging in a call.
As an alternative to the first approach, in a second approach, audio signals are not suppressed from being output from the user device during a call. By deliberately not suppressing audio signals from being output during a call, the user can listen to audio signals output from an application executing on the user device during a call. As an example, this approach allows a user to continue to listen to music output from his user device during a call. As another example, event sounds may be output from the user's device during an active call such that while the user is in an ongoing call an application handling the call may itself play sounds for other events (such as incoming instant messages or contacts in the communication system going on- or off-line), which occur during the call. Other applications that are running at the time of the active call at the user device may also output audio signals, as the user uses these applications while simultaneously engaging in the call.